1. Field of the Invention
The invention relates to spring biased drain closures for fluid containing vessels such as bathtubs and lavatories, and in particular to such a closure having a slidably attached drain plug and a latching mechanism for retaining the plug in a sealing position.
2. Description of the Related Art
Vessels such as bathtubs and lavatories are generally provided with a drain hole through which liquid retained within the vessel can be released. The drain hole is selectively opened and closed by a drain closure mechanism. A wide variety of drain closures have been previously disclosed, ranging from simple rubber plugs to lever operated devices.
Drain closures of the type having a plug or stopper which is vertically moveable between a sealed position and an open position but in which the plug or stopper is not easily removable from the drain opening are well known and commonly used in public establishments such as hotels and motels. Such a device is disclosed by U.S. Pat. No. 5,072,461 issued to Duane D. Logsdon and entitled Moveable Fitting Members for Use with Drain Fittings. The Logsdon patent shows a drain closure or xe2x80x9cfitting memberxe2x80x9d having a vertical guide post which threadably engages a drain fitting or strainer mounted in the drain hole. The guide post includes a bayonet pin or cross pin which extends outwardly from the guide post in opposing transverse directions. A plug or fitting member body is slidably mounted on the guide post to selectively close the drain opening. A nut attached to the top of the post prevents the plug from being removed. The plug includes a series of longitudinal slots or steps which engage the cross pin to hold the plug in the open position or in positions intermediate the open and closed position. The plug is held in the closed position by the weight of the plug and the weight of the water acting on the plug.
The Logsdon patent further discloses an alternative embodiment having lateral or bayonet slots which engage the bayonet pin to retain the plug in the open position or in positions intermediate the open and closed position. Once again, however, no lateral slot is provided for the closed position of the plug, which is only retained in the closed position by the force of gravity.
This device has at least two shortcomings: first, no provision is made for positively retaining the plug in the closed position; and second, the plug must be manually lifted into the open position against the weight of the water and twisted into the proper orientation to be retained in the open position. This second task can be difficult to accomplish by a user with wet, slippery hands. The configuration of the closure mechanism could also be problematic because a person taking a shower in a tub/shower combination using the device could easily kick or step on the plug and inadvertently knock it into the closed position, causing the water level to unexpectedly rise.
A solution to these problems is to produce such a device wherein the plug is biased into the open position and selectively positively retained in the closed position. Previous drain closures incorporating this feature (known as xe2x80x9cpop-upxe2x80x9d closures) are disclosed by U.S. Pat. No. 4,764,993 to Robert A. Oropallo and U.S. Pat. Nos. 4,103,372; 4,144,599; 4,339,823; 4,412,361; and 4,447,918 to Casper Cuschera. In these devices, the center post generally includes a tooth with a ramped upper surface and a generally horizontal lower surface. The plug includes a locking pin oriented to slide over the ramped upper surface on downward movement of the plug and to engage the lower surface as the plug begins to move upward. A compression spring is positioned between the top of the post and the plug to urge the plug upwardly. To open the closure, the user pushes downward on the plug against the bias of the spring and tilts it slightly to disengage the locking pin from the post tooth.
Pop-up closures of this type can be somewhat difficult for uninitiated users to operate. In order to properly open or close the device, the user must push down on the proper spot on the plug to tilt the plug in the correct direction to cause the locking pin to engage or disengage the post tooth. If the incorrect part of the plug is depressed, the plug will tilt in the wrong direction and will not lock or release as desired.
What is needed is a simple spring biased drain closure device which is easy to operate and relatively simple to manufacture and assemble.
The present invention comprises a drain closure for mounting in the drain hole of a vessel such as a bathtub or lavatory. The closure includes a strainer sized and shaped to fit within the drain hole and sealingly engage the vessel. The strainer includes an upstanding tubular wall defining a strainer passage and a spider spanning said strainer passage proximate the lower end of the tubular wall. At the upper end of the stainer, an annular flange extends radially outwardly from the tubular wall.
A post threadably engages a threaded receiver in the spider and extends upwardly therefrom in concentric orientation with the strainer passage. A pair of bayonet pins extend outwardly from the post in opposed transverse directions intermediate its upper and lower ends. The drain closure further includes a drain plug having a central aperture in sliding engagement with the post. The plug includes a pair of bayonet slots positioned in communication with the central aperture for slidingly engaging respective ones of the bayonet pins. Each bayonet slot includes a longitudinal portion extending upwardly from a lower extremity of the drain plug and a locking portion intersecting the longitudinal portion and extending laterally therefrom. An annular plug flange on the plug extends radially outwardly from the plug and is sized and shaped to cover the strainer passage. An elastomeric seal is positioned beneath the plug flange for sealingly engaging the strainer flange.
A cap is connected to the drain plug over the top of the central aperture. The cap includes an internal cavity in communication with the central aperture. A conical helical spring is positioned within the internal cavity such that a lower end of the spring engages the upper end of the post and the upper end of the spring engages the cap. The spring acts to bias the plug upwardly away from the strainer.
To close the drain closure, a user simply pushes down on the plug against the bias of the spring and twists the plug in a clockwise direction in order to rotate the locking portions of the bayonet slots onto the bayonet pins. To open the drain closure, the user need only rotate the plug slightly in a counterclockwise direction; the spring bias will urge the plug upward as soon as the bayonet pins encounter the longitudinal portions of the bayonet slots.